Thermal paste on cpu pins

my story:
as i said before i cleaned the old silver colour thermal paste on my pentium 4 cpu but accidentally some left between the cpu pins. i tried to clean it with just tissue paper and put it back. the computer boot, the xp operating system was fine but the motherboard speaker was making continuously noise.
first i thought the noise was coming from the cpu, graphic card or power supply fan , but i realize that it was the speaker from the motherboard. after a while i thought maybe the cpu pins were not clean properly.also i believed that the thermal paste is not conductive. because i didn't have acetone or alcohol , i used common washing liquid , water and and old toothbrush. i don't know about rusting but anyway the all cpu was cleaned very well and i let it dry.
after i applied carefully silicon based thermal paste and placed back the cpu on the motherboard . the computer boot fine and ther was no more noise from the motherboard speaker. So , the only thing i guess is that the silver thermal paste left between the cpu pins caused problems. and of course i am going to buy acetone or alcohol cleaning stuff.

Acetone is too dangerous. It can damage too many things. You don't want it around an open board... even the fumes are destructive unless you really know what you are doing.
Q-Tips, a very soft cotton cloth, and denatured alcohol applied patiently, dried, repeated, until you see nothing with a magnifying glass... and you are home free.

heh, I just wash mine under the tap with some dish soap and a toothbrush. Go gently on the pins.

Yea, right.